The present invention is in the field of die molding and compaction.
This invention relates to articles produced in a die molding process. More specifically, this invention relates to the determination of density gradients in molded components.
A variety of industries use compaction, as well as blow-molding, as a means of shaping material. This process is reasonably inexpensive and may be set up relatively easily. A problem exists with this procedure, however, in that density gradients are inevitable in all molding processes. These gradients can cause a host of processing problems downstream. These problems generally have an adverse effect on the cost of processing the molded parts. If the gradients are severe enough in a part, the least costly solution may be to reject or recycle the part, preferably prior to any thermal or other subsequent processing.
Unfortunately, density gradients are not detectable by the human eye. Expensive, sophisticated techniques are currently necessary to detect gradient variations in these parts, these techniques not being well. suited for a production environment.
It is therefore an object of the present invention to develop an inexpensive method of easily determining gradient variation of molded products in a production environment.
Although described with respect to the field of article molding and compaction, it will be appreciated that similar advantages of easy density visualization, as well as other advantages, may obtain in other applications of the present invention. Such advantages may become apparent to one of ordinary skill in the art in light of the present disclosure or through practice of the invention.
The present invention includes molding additives and molded materials. This invention also includes machines or electronic apparatus using these aspects of the invention. The present invention may also be used to upgrade, repair or retrofit existing machines or electronic devices or instruments of these types, using methods and components used in the art. The present invention also includes methods and processes for making and using these devices.
The present invention includes a method for detecting density gradients in molded articles of manufacture. The articles may be molded using any method known in the art, preferably compaction or blow molding. The method comprises, first, disbursing a fluorescence-capable dye in a molding additive, such as an organic-containing additive. It is preferred that the dye be capable of fluorescence due to infrared or ultraviolet absorption, most preferably due to ultraviolet absorption. The dye may be any appropriate such dye now known or subsequently discovered or developed.
The dye-containing additive is then disbursed or dissolved in a moldable material. If the moldable material is capable of properly dissolving or dispersing the dye alone, then the dye may be added directly to the moldable material and need not be added to a separate molding additive. The moldable material may be any appropriate material capable of being compacted or molded. The material is then molded into a shaped article.
The shaped article is then examined for fluorescence. The examination may be accomplished by any of several ways. A first method of examination involves directing a light source, preferably an ultraviolet or infrared light source, toward the shaped article. The light source should be capable of stimulating fluorescence in the fluorescence-capable dye. The shaped article is then visually inspected for variations in the resultant fluorescence of the article.
Another possible method of examination involves capturing at least one electronic image of the shaped article, the electronic image containing information regarding the fluorescence of the article. The electronic image is then analyzed. The image may be analyzed by any appropriate means, such as those involving quantitative determinations made by a computer or other processing device. These quantitative determinations preferably comprise density-fluorescence correlations.
Another method of examination involves passing a fluorescence detection device over the surface of the shaped article. The detection device is preferably connected to a feedback device, the feedback device adapted to signal when the fluorescence exceeds a threshold value. The signal may be any appropriate signal, such as a warning light, audible sound, or computer display. The fluorescence detection device may be moved over the article either manually or through the use of automation. Where automation is used, the automation apparatus may be adapted to remove from an assembly line or production process any articles wherein the fluorescence exceeds a predetermined threshold or where the variation in fluorescence exceeds a predetermined threshold.
An additional method of examination involves passing a microscope over the shaped article. The microscope may be any appropriate microscope adapted to detect fluorescence in a shaped article. The microscope may be a direct-view microscope or may utilize a camera connected to a computer or other display device. A user then views the shaped article using the microscope. The user may then make a determination as to whether the article passes inspection.